Fixing a Mixer?
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Posted on Apr 26, 2008 06:30 am
Novanium
Member Since: Feb 02, 2008
About a year ago i bought a no name powered mixer off of ebay for a steal. 350w at 4ohm out of 4 outputs, line level outputs, eq on everything, built in effects, and 8 channels, all with xlr inputs. For $100AU, i didn't mind that it didn't have phantom power.
Anyway, i screwed it up by using instrument cables instead of speaker cables. The powered outputs don't work anymore, and the line level outputs have a continuous buzz, making it impossible to record.
It's heavy, about 30kg, and i don't really want to drag it around too much. Does anyone know anything about fixing it, or where i could take it to fix it?
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pjkPrince CZAR-mingMember
Since: Apr 08, 2004
Apr 26, 2008 07:22 am Quote:
no name powered mixer
That will pose a problem. Schematics are a fixer's best friend. Try to get a name or something. It would help.
Quote:
i screwed it up by using instrument cables instead of speaker cables
That's odd, I wouldn't have thought you would break the mixer. Maybe overheat the cables. hmm, bummer if it did.
Power outputs are driving by finals, or high-output amplifying circuits. They may be replaced, as I've seen this done, but you'd want to know that they are actually bad. Testing for signal before the finals may work, but I don't know enough about them to walk you through it.
Also, it would seem odd that all go bad together. If a final goes, it would usually just take one output, or one side. Not both (or all 4, if they're separate) at the same time.
Also possible is the electrolytic capacitors can go bad. These caps help smooth out AC power into a flat DC power. If they are going bad, you'll start hearing the buzz you mention, so it could be indicative of your problem. When they go really bad, no power flows through parts of your system, like no output. So it could be e-caps are bad/and going bad.
Not knowing where you are, makes it tough to know where you could take it =).
I'm assuming you're in the land down under, as with paying 100au. If you have any TV repair shops, or stereo fixit shops around. Even a music shop may help, if they work on tube amps and such.
Be prepared for it to be more expensive to fix, than what you paid for it. It may not, but it's possible. if e-caps are gone, they'll need soldering to replace, same with finals.
If you don't get any real help, there's a guy over on Audiominds.com named Mac. He's been fixing problems like this for quite a while, and knows his stuff. He may be able to give you a few pointers, as I can only give guesses and ideas.
A model and make will help a ton, as will your level of DIY ability.
Apr 26, 2008 09:13 pm thanks for all of that;
it turns out the company doesnt make it any more, and i think i threw out the manual...
i'm not confident in doing anything myself, so i guess i'll drag it to a music store or something.
then again, theres another no name mixer on ebay for 150au; it's the same but it only has 4 inputs, but they have phantom power. might consider it.
WaltChief Cook and Bottle WasherMember
Since: May 10, 2002
Apr 26, 2008 10:28 pm As PJK mentioned a schematic would be real helpfull, I guess. Per your not being confident in diving into the thing, I would say not much. Sometimes, if the failure mode of a particular piece of equipment is common, folks can jump in and say, Ya, I had that one, it did exactly the same thing and I or I had the [watset or whosit #6] replaced, if you get my drift. But in terms of a generic mixer, the failure mode is a little odd for the perceived cause. Like pjk mentioned odd all of the output channels went out and possibly odd that the line outs are flaky, hard to say, some finals will effect prior amp circuits, some won't, also depending on what failed.
It's complicated.
Apr 27, 2008 05:29 am Well the reason i think that it was the cables is because when i brought my broken speakers (which broke when the mixer broke), the guy noticed i was using instrument cables and said "oooh, you might have blown your power amp" or something like that.
But it could also be because we were playing very loud, using instrument cables. Does that impact anything?
Anyway, I opened it up and had a peek inside, which wasnt easy as it would only open about 5cm without taking everything off, which i really didnt want to do.
The wires coming out of the inputs of the power amp were red and white, so i followed them. They lead to a small glass (or clear plastic) box with something in it (all i could see was a screw and a spring inside it). I assume that whatevers in that box might have broken, and i need it replaced.
Does that help at all?
WaltChief Cook and Bottle WasherMember
Since: May 10, 2002
Apr 27, 2008 10:03 am Ah no. not really.
There are about 2.6 kabillion ways the thing could have been engineered, and about 2.7 it could have failed. It isn't reall healthy to use instrument cables as power cables for sure, and it is possible at high output that could have caused the problem. Having said that, even if your cables are the smoking gun cause, it's darn near impossible to say what gave up the ghost in the mixer. Some stuff will pop a power supply before the finals (amplifiers) will go down. Some just have an inharent weak link that will crap out. At least now that you've opened it up you know that there's nothing livin in there!
